Monday, April 13, 2015

C language from BaseBand Processor Eng perspective Part-1

Well ...I have as of now worked for 3 years in IT industry, working as Baseband /Modem engineer.

Looking back at my work till now, it was limited mostly to C language.

Now preparing for new job and reflecting on the technologies, I was just thinking what actually is needed from a language when a person is working on it, more from modem eng perspective.


Now what is modem.  It is simply a processor/ chip in your mobile phones, whose functionality is to provide you with CALL , SMS , Supplementary Service , data /internet to your phones.

Now the modem protocols are defined by 3gpp body. It has already defined functions of each module and messages exchanged between different modules.

Now what we have to understand that modem codes run on a single processor ,( as I have seen till now) . Also it doesn't have any complex data structures  like tress, graphs etc. Most of times it will be array / linked list.

What we will find extensively in modem codes are function pointers, structures , enums and typedef.

Each module will register a callback functions to other modules to wait for a event. Also it will allocate memory for its structures. Checking of parameters received and typecasting them will be present. Then the new message data structure will be sent to other module.

Other thing which we have to learn and see is that in modem codes a lot of message posting / mailbox will be seen. Also mobile phones have Application Processor which will exchange messages with the baseband processor. That will need IPC ( Inter Processor Communication).

Lets see do you find anything good in next some lectures.

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